Should i connect a 5gpu rig directly to the wall? or should i use an automatic voltage regulator?

thank you guys i just want to know as the title says, as i was using one voltage regulator that started to smell like burned, but it was after i conected to it one 4 of rx 470 rig + monitor + another pc with one rx 470 (non mining on the second pc)

a friend of mine said that its ok to put the miner directly on the Wall, but wanted to make sure.


thanks again